As is generally well known, cardiopulmonary resuscitations (CPR) is an emergency procedure used to treat victims of cardiac and respiratory arrest. When performed as a first-aid procedure, until aggressive techniques such as employing drugs and defibrillation equipment can be administered, it combines external heart massage, to keep the blood flowing through the body, with artificial respiration, to keep air flowing in and out of the lungs. The victim is placed face up. The person administering CPR places his or her hands, one on top of the other, with fingers interlocked, heel down on the victim's breastbone, leans forward, and makes 30 quick, rhythmical compressions, at a rate of about one per second, of about 2 in. This is followed by two breaths, administered using the mouth-to-mouth method of artificial respiration. CPR for infants and children differs in the ratio of compressions to breaths, and the compression of the chest is only 1 to 1.5 in. Ideally, the procedure is performed by two people, one to give mouth-to-mouth artificial respiration and one to apply external heart massage.
It is understood that CPR is a practical skill and that competency in CPR technique is particularly important. CPR training begins with professional instruction and is followed up by regular practice on a resuscitation mannequin to gain and maintain full competency.
However, even when the procedure is performed by professional personnel, it is common to cause cartilage separation. Furthermore, since chest compressions must go very deep and since the hand overlaps the width of the breastbone, it is not uncommon to crack ribs of the victim, while shallow compressions may lead to low or no blood flow to the brain of the victim. Additionally, the victim may vomit during the procedure, which is in stark contrast to the clean environment that CPR was taught in and it is important for the person administering CPR to take precautions, by way of gloves and mouth guard, against bodily fluids, particularly blood and reflux discharge.
Attempts have been made to resolve the problem of excessive or insufficient compressions. For example, U.S. Pat. No. 4,077,400 to Harrigan discloses a small inflatable “pillow” which has a pressure gage calibrated to read out the downward force or pressure applied to the victim's chest. However, Harrigan focuses only on the pressure or the applied manual force and does not address the depth of the chest compression that is extremely desirably for a proper CPR procedure.
U.S. Pat. No. 5,657,751 to Karr, Jr. teaches an extremely complex manually operated pump which includes a cylinder and a piston slideably mounted within the cylinder and connected by way of an air line to the mask placed over the victim's mouth.